arXiv subjects
Publications and source records attributed to A. V. Kisselev.
A production of a pair of tau leptons in PbPb collisions at the FCC-hh collider is examined. The 95\% C.L. exclusion limits, as well as 3$σ$ and 5$σ$ sensitivity limits on the anomaly magnetic moment of the tau lepton $a_τ$ and its electric dipole moment $d_τ$ are obtained. A comparison with bounds on $a_τ$ and $d_τ$ for other future colliders are given.
A virtual production of heavy axion-like particles (ALPs) via light-by-light scattering in pp, pPb and Pb collisions at the future 100 TeV collider FCC-hh is studied. Both differential and total cross sections are calculated. The 95\% C.L. exclusion limits, as well as $3σ$ and $5σ$ discovery limits on an ALP coupling constant versus ALP mass $m_a$ are given, using integrated luminosities of 30 ab$^{-1}$, 27 pb$^{-1}$ and 110 nb$^{-1}$. Our results are compared with the current LHC bounds. The strongest limit on the ALP coupling is obtained if $m_a \simeq 250$ GeV for the PbPb collisions, and if $m_a \simeq 1$ TeV for pp or pPb collisions. This suggests that the FCC-hh has a great physics potential of searching for the heavy ALPs.
A sensitivity of the collider FCC-hh to anomalous quartic gauge couplings (aQGCs) of neutral bosons in lead-lead collisions is studied. Examining diphoton production, the bounds on aQGCs at $5σ$ and 95\% C.L. are obtained depending on systematic uncertainties.
We examine a contribution of axion-like particles (ALPs) to a top pair production via the collision of Compton backscattered photons at the CLIC operating in a $γγ$ mode. The exclusion bounds on the ALP-top quark coupling depending on the ALP mass $m_a$ are given. The mass range 10 GeV -- 10 TeV is considered. We have obtained that for $m_a = 10$ GeV the ALP-top quark couplings as small as $0.17$ TeV$^{-1}$ and $0.11$ TeV$^{-1}$ can be probed at the CLIC with the energy of 1.5 TeV and 3 TeV, respectively. A comparison with other constraints on the ALP-top coupling is given.
The sensitivity to anomalous quartic gauge couplings (AQGCs) of the $γγγZ$ interaction is studied in the $μ^+μ^- \rightarrow μ^+γγμ^-$ scattering at a future muon collider with unpolarized beams. The anomalous $γγγZ$ vertex is described by two couplings, $ζ_1$ and $ζ_2$. The differential and total cross sections are calculated for the center-of-mass energies of 3 TeV, 14 TeV, and 100 TeV. For these values of the collision energy the $95\%$ C.L. exclusion regions for AQGCs are obtained depending on the systematic error. In particular, for the 14 TeV muon collider with the integrated luminosity $L = 20$ ab$^{-1}$ the best sensitivities are derived to be $ζ_1 = 3.1 \times 10^{-5}$ TeV$^{-4}$ and $ζ_2 = 6.5 \times 10^{-5}$ TeV$^{-4}$. These constraints are three orders of magnitude stronger than the bounds obtained for the 27 TeV HE-LHC with $L = 15$ ab$^{-1}$. At the 100 TeV muon collider with $L = 1000$ ab$^{-1}$ AQGCs can be probed up to $(1.64 ÷3.4) \times 10^{-8}$ TeV$^{-4}$. The partial-wave unitarity constraints on couplings $ζ_1$, $ζ_2$ are evaluated. It is shown that the unitarity is not violated in the region of the AQGCs examined in the present paper.
We have studied anomalous four-photon couplings in the $μ^+μ^- \rightarrow μ^+ γγμ^-$ scattering at a future muon collider. The collision energies of 3 TeV, 14 TeV, and 100 TeV are addressed. Both differential and total cross sections versus invariant mass of the outgoing photons are calculated. The best 95\% C.L. exclusion bounds on anomalous couplings are obtained to be $g_1 = 2.23 \times 10^{-8}$ TeV$^{-4}$ and $g_2 = 4.22 \times 10^{-8}$ TeV$^{-4}$. They correspond to the muon collision energy of 100 TeV. The partial-wave unitary constraints on $g_1$ and $g_2$ are examined. We have demonstrated that the unitarity is not violated in a region of the anomalous couplings obtained in the present paper.
We have examined inclusive $μ^+μ^- \rightarrow μ^+ μ^- + E_{\mathrm{miss}}$ and annihilation $μ^+μ^- \rightarrow μ^+ μ^-$ processes at future high energy muon colliders in the framework of the Randall-Sundrum-like model with a small curvature of space-time. The collision energies of 3 TeV, 14 TeV and, 100 TeV are addressed. Both differential and total cross sections are calculated, and exclusion bounds on a 5-dimensional gravity scale are obtained depending on collision energy and integrated luminosity of the muon colliders.
We have examined the sensitivity to the axion-like particle (ALP) couplings to electroweak gauge bosons in the diphoton production at a future muon collider. The collisions at the $μ^+ μ^-$ energies of 3 TeV, 14 TeV, and 100 TeV are addressed. The differential cross sections versus the invariant mass of the final photons and total cross section versus minimal diphoton invariant mass are presented. We have derived the exclusion regions for the ALP-gauge boson coupling. The obtained bounds are much stronger than the current experimental bounds in the ALP mass region 10 GeV -- 10 TeV. The partial-wave unitarity constraints on the ALP-gauge boson coupling are estimated. We have shown that the unitarity is not violated in the region of the ALP coupling studied in the present paper.
The noncommutative QED (NCQED) has a non-Abelian nature due to the presence of 3- and 4-photon vertices in the lagrangian. Thus, NCQED predicts a new physics contribution to the $γγ\rightarrowγγ$ scattering already at the tree level. We have examined NCQED by studying the light-by-light process at the 14 TeV LHC with intact protons. Our results show that the NC scale up to $Λ_{\mathrm{NC}} = 1.65(1.35)$ TeV can be probed in the $pp\rightarrow p(γγ)p \rightarrow p'(γγ)p'$ collision for the time-space (space-space) NC parameters. These bounds are stronger than the limits that can be obtained in the light-by-light scattering at high energy linear colliders.
For the first time, the production of a massive dark photon (DP) in the $γe^-$ scattering at the future lepton colliders ILC, CLIC, and CEPC is examined. The invisible decay mode of the DP is addressed. We have studied both the unpolarized scattering and the collision of the Compton backscattered photons with the polarized electron. The missing energy distributions are shown. We have considered the wide range 10 GeV -- 1000 GeV of the DP mass $m_{A'}$. The excluded regions at the 95\% C.L. in the plane $(\varepsilon, m_{A'})$, where $\varepsilon$ is the kinetic mixing parameter, are obtained.
We have estimated the sensitivity to the anomalous couplings of the $γγγZ$ vertex in the $γγ\rightarrowγZ$ scattering of the Compton backscattered photons at the CLIC. Both polarized and unpolarized collisions at the $e^+e^-$ energies 1500 GeV and 3000 GeV are addressed, and anomalous contributions to helicity amplitudes are derived. The differential and total cross sections are calculated. We have obtained 95\% C.L. exclusion limits on the anomalous quartic gauge couplings (QGCs). They are compared with corresponding bounds derived for the $γγγZ$ couplings via $γZ$ production at the LHC. The constraints on the anomalous QGCs are one to two orders of magnitude more stringent that at the HL-LHC. The partial-wave unitarity constraints on the anomalous couplings are examined. It is shown that the unitarity is not violated in the region of the anomalous QGCs studied in the paper.
The anomalous quartic neutral couplings of the $γγγγ$ vertex in a polarized light-by-light scattering of the Compton backscattered photons at the CLIC are examined. Both differential and total cross sections are calculated for $e^+e^-$ collision energies 1500 GeV and 3000 GeV. The helicity of the initial electron beams is taken to be $\pm\,0.8$. The unpolarized and SM cross sections for the same values of helicities are also estimated. The 95\% C.L. exclusion limits on two anomalous photon couplings $ζ_1$ and $ζ_2$ are calculated. The best bounds on these couplings are found to be $6.85 \times 10^{-16} \mathrm{\ GeV}^{-4}$ and $1.43 \times 10^{-15} \mathrm{\ GeV}^{-4}$, respectively. The results are compared with the exclusion bounds obtained previously for the LHC and HL-LHC. It is shown that the light-by-light scattering at the CLIC, especially the polarized, has a greater potential to search for the anomalous quartic neutral couplings of the $γγγγ$ vertex.
We trace what happens with asymptotically free behavior of the running coupling in $ϕ^{3}$ theory in six-dimensional space-time if to compactify two spatial dimensions on a 2D closed manifold. The result can be considered as an effective 4D theory of infinitely many KK-type scalar fields with triple interactions. The effective \emph{dimensional} coupling inherits running to zero at high mass scales in a modified form depending on the size of the compact manifold. Some physical implications are discussed.
The light-by-light (LBL) scattering with initial polarized Compton backscattered photons at the CLIC, induced by axion-like particles (ALPs), is investigated. The total cross sections are calculated, assuming CP-even coupling of the pseudoscalar ALP to photons. The 95\% C.L. exclusion region for the ALP mass $m_a$ and its coupling constant $f$ is presented. The results are compared with previously obtained CLIC bounds for the unpolarized case. It is shown that the bounds on $f$ for the polarized beams in the region $m_a = 1000 \mathrm{\ GeV} - 2000 \mathrm{\ GeV}$, with the collision energy 3000 GeV and integrated luminosity 4000 fb$^{-1}$, are on average 1.5 times stronger than the bounds for the unpolarized beams. Herewith, our CLIC bounds are stronger than all current exclusion regions for $m_a > 80$ GeV. In particular, they are more restrictive than the limits which follow from the ALP-mediated LBL scattering at the LHC.
The photon-induced dimuon production $e^+ e^- \to e^+ γγe^- \to e^+ μ^+ μ^- e^-$ at the CLIC is studied in the framework of three models with extra dimensions. The electron beam energies 750 GeV and 1500 GeV are considered. The total cross sections are calculated depending on the minimal transverse momenta of the final muons. The sensitivity bounds on the parameters of the models are obtained as functions of the CLIC integrated luminosity.
The virtual production of axion-like particles (ALPs) in the light-by-light scattering at the CLIC collider is studied. Both differential and total cross sections are calculated, assuming interaction of the ALP with photons via CP-odd term in the Lagrangian. The 95\% C.L. exclusion regions for the ALP mass and its coupling constant are given. By comparing our results with existing collider bounds, we see that the ALP search at the CLIC has a great physics potential of searching for the ALPs, especially, in the mass region 1 TeV -- 2.4 TeV, with the collision energy $\sqrt{s} = 3000$ GeV and integrated luminosity $L = 5000$ fb$^{-1}$ for the Compton backscattered initial photons. In particular, our limits are stronger that recently obtained bounds for the ALP production in the light-by-light scattering at the LHC.
The Hankel transform H_n[f(x)](q) = int_0^infinity xf(x)J_n(qx)dx is studied for integer n>=-1 and positive parameter q. It is proved that the Hankel transform is given by uniformly and absolutely convergent series in reciprocal powers of q, provided special conditions on the function f(x) and its derivatives are imposed. It is necessary to underline that similar formulas obtained previously are in fact asymptotic expansions only valid when q tends to infinity. If one of the conditions is violated, our series become asymptotic series. The validity of the formulas is illustrated by a number of examples.
The eikonal approximation for the total cross section for the scattering of two unpolarized particles is studied. The approximate formula in the case when the eikonal function chi(b) is moderately small, |chi(b)| < 0.1, is derived. It is shown that the total cross section is given by the series of multiple improper integrals of the Born amplitude A_B. Its advantage compared to standard eikonal formulas is that the integrals contain no rapidly oscillating Bessel functions. Two theorems which allow one to relate large-b behavior of chi(b) with analytical properties of the Born amplitude are proved. Several examples of these theorems are given. To check the efficiency of the main formula, it is applied for numerical calculations of the total cross section for a number of particular expressions of A_B. Only those Born amplitudes are chosen which result in moderately small eikonal functions and lead to the correct asymptotics of chi(b). The numerical calculations show that our formula approximates the total cross section with the relative error of O(10^(-5)), provided that the first three non-zero terms in it are taken into account.